But the airlines might decrease and enforce the cabin luggage weight/size limits, so as to give a better fit to the present luggage bins...
As we have discussed in this forum before: That ain't gonna happen no time soon. I consider that, if one carrier
did enforce the rules, many pax would abandon that carrier. They see the carry on as a 'free' and expectected part of the ticket price'. Other carriers would benefit and see that they ought not to follow. If it were possible for ALL carriers to enforce ALL the rules ALL the time ... well we would see Capt Danny's Pig overtake him in the cruise!!
When tested, the bins have only to withstand a static weight limit.
Indeed, as born out by the statistic that pax sitting in aisle seats have more injuries at all stages of the flight (ground and airborne) and that is before you hit turbulence. It is the second reason that I always sit in a window seat. If I am in the aisle and someone reaches to the bin over my heard - then I try to get up and out of their way.
It would be a neat idea to make the bins smaller but we have seen the manufacturers make the bins larger and stronger in recent years and the only reason can be because the carriers asked them to.